Can I wash my hands with plant fertilisers? Is that safe? Not exactly, even though both plant liquid fertilisers and soap contain potassium hydroxide.

Potassium hydroxide (KOH), most commonly referred to as lye or caustic potash, is an inorganic compound. It’s marketed in several forms which includes pellets, powders and flakes. It is used in various chemical, industrial, and manufacturing applications.

Potassium hydroxide has a wide range of applications including food production, consumer care and pharmaceuticals, agriculture and glass manufacturing.

It’s also used as an electrolyte in the production of alkaline batteries, as a de-icer for airport runways and in the manufacturing of biodiesel.

But two of the well-known uses is the production of liquid plant fertilisers and soap:

Since potassium is one of the main nutrients required for plants to grow and reproduce, its no surprise that potassium hydroxide is an important chemical used in the manufacturing of liquid fertiliser mixtures. Its low salt index and high solubility helps to increase crop yield and improves the drought tolerance of crops.

In soaps, both alkali’s, potassium hydroxide and sodium hydroxide can be used to produce soap. Because potassium hydroxide is slightly smaller than sodium hydroxide, which means it can cut through oil molecules faster, it is the perfect choice for soaps that need to remove caked-on oil.

Nobody would consider washing themselves with oven cleaner or plant fertiliser, so how then is it possible that one chemical can produce two very different products?

Lye is used in small amounts in cosmetics to modulate the pH of the product. It’s also used as a cleansing agent, most often in pure soaps or soap hybrid products. But as a side note it’s also important to know that in higher concentrations, potassium hydroxide can aggravate skin, even if used in rinse-off products. All ‘REAL’ soap is made with lye. Any skin or hair cleansing product made without sodium hydroxide or potassium hydroxide is not classified as a soap, but rather as a detergent.

But the term “Lye” is not always used directly on the soap bar’s ingredient list

If it is real soap or contains real soap, it must be made with lye! However, this is not always listed on the packaging. Other terms or words that are being used in the place of ‘lye’ include saponified oils, sodium cocoate, sodium palmate, sodium palm kernelate, sodium tallowate and sodium olivate. 

Incorrect and reckless use of potassium hydroxide can be hazardous

Potassium hydroxide is extremely corrosive and can cause severe burns to skin, eyes, the respiratory tracts (if inhaled) and the digestive tract (if digested).

Here’s what you need to know:

Inhalation – Effects from inhalation of potassium hydroxide dust or mist can vary from mild irritation to serious damage of the upper respiratory tract, depending on the severity of exposure. Symptoms may include coughing, sneezing, damage to the nasal or respiratory tract. High concentrations can cause lung damage. If inhalation has occurred, remove the person into an area with fresh air. If they are not breathing, give artificial respiration. If breathing is difficult, give oxygen. Call a physician immediately or get them to a hospital.

Ingestion – Potassium hydroxide toxic when ingested. Swallowing may cause severe burns of the mouth, throat and stomach. Other symptoms may include vomiting, diarrhoea. Severe scarring of tissue and death may result when a dose of 5 grams of more is ingested. If ingestion has occurred, DO NOT INDUCE VOMITTING. Give the person large amounts of water and seek medical attention immediately. Never try to give an unconscious person water or anything by mouth.

Skin Contact: Since potassium hydroxide is corrosive, contact with the skin can cause irritation or severe burns and scarring with greater exposures. If someone has come into physical contact with potassium hydroxide, remove clothing and flush the area with water for at least 15 minutes. All clothing that has been exposed (including shoes) must be washed thoroughly before reuse. If skin burns have occurred, seek medical attention.

Eye Contact: Small amounts of exposure to the eyes can cause irritation of eyes with tearing, redness and swelling. Greater exposures cause severe burns which can result in possible blindness. If contact with the eyes has happened, Immediately flush eyes with plenty of water for at least 15 minutes while lifting the lower and upper eyelids occasionally. Get medical attention immediately.

Chemtoll specialises in bulk potassium hydroxide manufacturing at competitive prices. Contact us on +27 21 842 2963 for a need’s analysis, a comprehensive quote, or for more information potassium hydroxide or the other products we offer.